This invention relates to a resin composition and a molded product thereof which are useful as component materials for various automobile parts, machine parts, electric or electronic parts and component materials for general merchandise.
Thermoplastic polyesters typified by polyethylene terephthalate and polybutylene terephthalate have superior mechanical properties, in particular, a high rigidity and strength, and are widely used as superior engineering plastics. On the other hand, polyamides such as polycaproamide and polyhexamethylene adipamide are utilized as important materials in the field of molding products having different uses from those of polyesters, making the most of their superior toughness, wear resistance and chemical resistance.
It has been hitherto attempted to combine such polyesters and polyamides to utilize the superior properties possessed by each of them, and also to settle the problems possessed by each of them. For example, Japanese Patent Publication Nos. 19101/1972 and 24465/1972, Japanese Unexamined Patent Publication Nos. 56742/1973, 114661/1974, 34754/1981 and 49657/1982, etc. disclose techniques in which the composition for compounding polyester and polyamide is varied respectively depending on purposes or fibrous reinforcing materials and inorganic fillers are used in combination as additives in order to settle the problems arising when the polyester and polyamide are combined.
In instances in which the polyester and polyamide are mixed, usually applied is a melt kneading method, but no homogeneous kneaded products can be obtained because of poor compatibility between polyester and polyamide, bringing about the problems that molded products obtained from such kneaded products have poor mechanical properties and a great scattering of the mechanical properties is seen for each molded product. Among such problems, particularly questioned are a low impact strength or tensile elongation of the molded products and a great scattering of heat distortion temperature, and moreover it may further occur that layer separation is caused in the molded products when they are used. There is also another problem that since the polyester which is a constituent component of the kneaded products causes a lowering of molecular weight because of its hydrolysis, the mechanical properties are lowered when the molded products are immersed in hot water for a long time. Accordingly, owing to such problems, the component materials comprising the combination of polyester and polyamide are applied to various fields with obstruction.
In the instances in which the polyester and polyamide are mixed, usually applied is a melt kneading method, but no homogeneous kneaded products can be obtained because of poor compatibility between polyester and polyamide, as mentioned above. To solve such a problem, studies have been made on methods in which various compatibilizing agents are added. However, the mechanical properties, particularly flexural rigidity, of the products thus formed by kneading polyamide and polyester necessarily depend on the flexural rigidity of the compositions compounded therein.